A presentation of student research

Under the Kyoto Protocol, Denmark has an obligation to reduce its CO2 emissions by 21 percent. Expansion of wind power is one of the relevant measures to realize this target. Negative externalities in terms of visual disamenities and noise nuisances may make it difficult to find new areas suitable for land-based wind turbines. Offshore wind farms have taken the forefront and seem to bypass some of these difficulties. Denmark is one of the leading countries in offshore wind energy generation and also one of the pioneers.

Installation and Developments

Nysted was once the largest offshore wind farm in the world, but has since been eclipsed by Anholt, currently the largest wind farm in Denmark, and the third largest in the world. Nysted is approximately 10 kilometers offshore of the town by the same name and was constructed in waters that run 6-9 meters deep. For the construction of one wind turbine much of the sand had to be removed at the sea floor and chipping was laid down to allow the turbines to be level and rest on “firm ground,” according to the Nysted official website. The foundation was then laid with additional gravel on top to provide even more weight. This initial step of the installation provides the turbines with enough weight to keep them stationary at about 1,600 to 1,800 tons. The tower was then erected in three stages, with the rotor coming on last. At this point, the wiring is fitted within the tower itself and laid on the ocean floor to make its trek back towards land and provide energy. This wiring, however, was already laid to prevent possible delays in the commission date of the wind farm, according to Per Volund.

According to data from the 4C Offshore website Nysted has been operational for a decade now and has been fully functioning an astounding 98% of the time. This is corroborated in part by a report written by Per Volund, et al which shows that one year after commission the wind farm was still running very well. This report states that one of the turbines was hit by a particularly strong bolt of lightning, but little to no damage was sustained. Additionally, it is predicted that the turbine will only have to be visited twice per year for potential damages, which includes one visit per year for planned maintenance.

Nysted Offshore Wind Farm (Photo: DONG Energy)

Environmental Conditions

Some important characteristics should be noted about the environmental conditions of the Nysted wind farm. The location, as noted above, is approximately 10 kilometers to the south of the town Nysted, which is situated on the southeastern coast of Lolland, an island in Southern Denmark. The wind farm consists of 72 bonus turbines, which produce 2-3 megawatts each, for a combined capacity of 166 MW. The turbines are situated in 9 rows, each containing 8 units, ranging in depth from 6-9 meters. The end result of this mechanical feat is the production of 570 gigawatt hours, which is comparable to fulfilling the electricity needs of 140,000 Danish households (Chen et al, 2009).

In order to understand the full extent of the environmental impacts resulting from construction and function of the wind farm, an environmental group was assembled to be headed by the Danish Energy Agency, the Danish National Forest and Nature Agency, the Danish Energy Agency, Vattenfall, and DONG Energy. During the permit application procedure, this environmental task force was instructed to conduct a program that would achieve the goal of monitoring the environmental situation prior to, during, and after construction of the wind farm. The program also encompassed an international review, where a group called The International Advisory Panel of Experts on Marine Ecology would be called upon annually to assess the findings of the environmental group’s report and suggest areas where further research was necessary. The environmental group branched out even further to touch base with the concerns of various domestic and international conservational organizations, including the World Wide Fund for Nature, the Danish Society for the Conservation of Nature, Greenpeace, and the Organization for Sustainable Energy.

Environmental Impact

One of the main concerns in monitoring the environmental impacts of the Nysted wind farm involved its proximity to a nature reserve, found 2 km away, as well as the Rodsand seal sanctuary, situated 4 km away. The goals were primarily to monitor how construction work would influence the interaction between marine ecosystems, and involved the limitation and purposeful selection of those permitted to travel through the area. While there were a multitude of environmental issues that the group addressed, the factors that were continuously addressed included: sediment spill monitoring, incident reports, oil spill accidents, transportation of waste materials, considerations brought about from pile driving, deposition of sediments, and the composition of the seafloor (Dong Energy et al, 2006).

The naturally favorable environmental conditions for offshore wind in Denmark facilitated the creation of a thorough environmental impact assessment process that would later establish the standard for offshore wind developments throughout the European Union. In 1998, five years before the construction of Nysted, the Danish government solicited two of the nation’s largest utility companies to assist in creating an environmental demonstration program in order to establish a framework for the approval process (Danish Energy Agency, 2013.) In making a comprehensive approval process, the intent of each involved party was to ensure that wind energy was not mutually exclusive from environmental and social interests. Thus, the environmental monitoring program was made with two distinct components. The first, performed from 2000-2006, established a Before After Impact Control (BAIC) assessment to compare baseline conditions with any changes after construction and operation, followed by subsequent environmental analysis (Danish Energy Agency, 2103.) The second, examined from 2007 until present, was purposed to implement solutions that would mitigate any potential environmental issues. The preliminary BAIC encompassed five main environmental concerns: changes in benthic community structure and effects on fish, birds, and marine mammals.

The seabed around Nysted consisted almost entirely of sandy sediments before construction. The implementation of solid pile foundations changed the benthic dynamic from infauna to hard bottom communities. Although these results cited changes in ecosystem structure, preliminary analysis concluded positive effects on abundance and biomass in benthic communities (Danish Energy Agency, 2013.) In a similar vein, changes in benthic structure had minor impacts on fish populations. This is because density in the benthic community increased, but primarily in one species, large common mussels (Danish Energy Agency, 2013.) Moreover, the benthic monoculture created by this particular species is only moderately attractive for creating a diverse fish habitat (Danish Energy Agency, 2013.)

For bird populations, the site saw reductions in densities after construction of the wind farm. In particular, the long-tailed duck saw significant avoidance of the area after construction (Petersen, et al, 2006.) In construction of the wind farm, researchers were most concerned with the impacts on migratory bird species that passed over the area in the autumn months. Researchers used radar monitoring to examine the abundance of migrating birds and extrapolate collision modelling and monitoring data (Danish Energy, 2013.) Results showed minimal risks of collision in the migratory path (Danish Energy Agency, 2013.)

The primary marine mammal examined in the BAIC assessment was the harbor porpoise. Although porpoise densities in the western Baltic, where Nysted is located, are typically low, researchers took several steps to minimize impact on these marine mammal communities. Since pile driving generates high sound pressures, construction can cause auditory damage to animals at a close range. Thus, engineers working on the project gradually increased pile driving activities and employed underwater alarm systems, known as seal scarers, to deter porpoises from inhabiting the area during construction (Tougaard et al, 2004.) After construction, researches used acoustic monitoring to investigate porpoise activity around the wind far from construction until 2006. Results concluded that porpoise prevalence decreased from the impact area to reference stations ten kilometers away from construction to the first year of operation (Tougaard, et al, 2004.) This can be attributed to either local ship traffic during the construction phase or to temporary energy to echolocation behavior. The latter is most probable, seeing that the acoustic behavior of porpoises in the area returned to baseline expectations in the second year of operation (Tougaard, et al, 2004.) The general conclusion explaining minimized porpoise interaction at Nysted is that because the species is disinterested in the habitat before environmental disturbance, they will especially stay away when it is introduced. Moreover, the sheltered nature of Nysted makes the turbine noise more distinctive at higher distances, causing porpoises to shy away from habitat creation (Tougaard, et al, 2004.) As a result, geographical elements in addition to anticipated effects from construction make Nysted a less than ideal habitat for porpoises, but only in the short term.

Using the data gathered from 2000-2006, the International Advisory Panel of Experts in Marine Ecology (IAPEME) made mitigation recommendations which informed the second phase of the environmental impact assessment (Danish Energy Agency, 2013.) In short, the main focus of follow-up program was to continue data acquisition over the long term that will inform more substantive analysis within the next decade (Danish Energy Agency, 2013.) During the BAIC assessment, most of the effects on wildlife at Nysted were negligible, largely because the area was unfavorable to most species before construction. The second phase of assessment will reveal whether the wind farm invites greater biodiversity, or has remains to have little impact on species.

Financing and Infrastructure

The wind farm is owned by Dong Energy, Stadtwerke Lübeck, and PensionDanma. However, DONG Energy was responsible for erecting the turbines and making the foundations, which constituted 80 percent of the total costs (Nysted.) Quantitative data for the total costs is difficult to find, but the 4c Offshore website, an international database for offshore wind energy data, shows a stated cost of €245 million.

The Danish Action Plan on Offshore Wind was established in 1997 which set a requirement for utilities to research and develop offshore wind capabilities. This allowed for the streamlining between local and government authorities and the appropriate utility companies by the time Nysted was considered for construction as noted in a report by the Danish Energy Authority in 2006. This is likely what led to its success as the first major wind farm internationally. The approval process started in 1999 the first surveying was start. In 2001 after the EIA (Environmental Impact Assessment) was completed Nysted was approved. This is a drastic difference from what we see in the U.S. today. Cape Wind in the Nantucket Sound, for example, has been in the preliminary phases since 2004 and construction still has not begun. It is clear with the proper government backing that wind farms can be approved very quickly and this could be a technology that we implement very effectively in short order.

Conclusion

At ten years Nysted is still running very efficiently and appears to be fulfilling all of the hypotheses given by Per Volund. Nysted, being one of the first wind farms and at the time the biggest, provided a valuable benchmark to the rest of the world. According to an article on the Dong Energy website (a major stakeholder in the wind farm) many neighboring countries, particularly Germany and the UK are receiving training on how to successfully run a wind farm. It is unclear if Nysted is the ideal benchmark that Dong may want us to believe, but it is very clear that major increase in wind energy has been seen in the past several years. Denmark, and Nysted, were at the forefront of this and do deserve major credit.